Packing tube



y 1954 A. NORDEAN 2,679,344

PACKING TUBE Filed Jan. 8, 1948 INVENTOR ALBER NORDEAN BY fizm; 6 340,04

4] TORNE Y Patented May 25, 1954 UNITED STATES Par-suror-rrirzs Albert Nordean, Spokane, Wash, assignor to General Mills, Inc., a corporation ofDelaware Application January 8, 1948, Serial No..1,155

7 Claims. 1

This invention relates to an improvement; in packing tubes of the type used for filling bags or other containers with powdered material. The invention is particularly concerned with packing tubes for flour in which a packing auger is included within the tube.

Packing machines for powdered material in which an auger forces the material through the tube and into a bag into which the tube has been inserted are well known in the art. In such devices there is a tendency for the flour or other powdered material to boil over or overflow at certain points around the mouth of the bag. The reasons for such boiling are not clearly understood. Various proposals have been made in the past to avoid such overflow and these proposals are often contradictory in nature and theory. Thus, on the one hand, it has been suggested that the filling tube and bag should-be so constructed and arranged that there will always be an air space around the tube to permit the air to escape and avoid boiling. On the other hand it has also been proposed that the only way to avoid boiling is to provide a tight seal between the packing tube and the mouth of the bag. Neither of these proposals has proven entirely satisfactory.

With the disadvantages and contradictory teachings of the prior art in view, it is-accordingly one object of the present invention to provide an improved packing tube or spout for filling powdered materials, which shall eliminate boiling over of the material at the mouth of the container which is being filled.

It is a further object of the invention to provide a filling tube with a projection or blister located on one side only of the tube for preventing such overflow.

Still another object is to provide means on a packing tube for positioning the bag with its axis laterally ofiset from the axis of the tube and with an air escape passage between the periphery of the tube and the inner walls of the bag. Other objects and advantages of the invention will be apparent from the following specification in which a detailed description of the invention is given. The drawings which accompany this description show one embodiment of the invention by which the foregoing objects and advantages are achieved.

In these drawings, wherein like reference characters indicate like parts,

Figure 1 is a side elevation of a filling spout and bag according to the invention, with certain parts broken away and certain portions shown in section for the sake of clearness.

.sourceoi supply of the material to bev packed.

Wi-thin'the tube #0 a packing auger $2,.in substantially the form of a screw conveyor, may be located. Auger i2 is connected to a driving shaft it which in turn is driven in any desired fashion. The. dimensions of the auger-are such that there will be some clearance, as at I4, be-

tween the edges: of the screw and the inner surface of the wall of tube It. It will be obvious that suitable'rotation of shaft l3 and anger l2 will force the powdered material, such as flour, downwardly and out of the open lower end l5 of tube Ill.

.Asis well known in the art, it is customary to positions.v bag ill or equivalent container around the outside of the filling tube iii so that the tube projects substantially to the bottom of the bag. As the, material is forced from the tube, the bag is gradually lowered from the heavy line position of Fig. l to the dotted line position in said figure. This handling of the bag may be accomplished either byhand or by suitable machinery which need not be described here since it forms no part of the present invention.

To prevent. the boiling over of the flour or other material atthe mouth of the bag during this filling operation, I have provided a projecting portion designated generally as 1?. This pro jection or blister is located at only one side 1 of the tube and I prefer to position it on the side of the tube toward the operator of the machine. In the preferred form of the invention shown in the drawings, this projection consists of upper .and lower tapering sections l8 and !9 which are joined together by weldin or other-suitable means at their line of intersection 20 which extends. substantially horizontally as shown. Upper and lower horizontal or circumferential flanges 2| and 22serve to join the top and bottom of .upperand lower sections 18 and is respectively to the outer surface of tube It at points above and below the line of intersection 20. Similarly, vertical or axial flanges 23 arefastened tothe surface of the tube to join the sides of projection ll thereto.

The projection ispreferably located near the end of the tube, 1. e., somewhere in the lower third of the tube, so that it will be continuously which may be in the form of an arc, the radius' of which is smaller than the radius of tube I0. In this case, the center of the circular are 20 is located at the point 26 which is inside the circumference of tube [0. This circular arc ex-.

tends each way from a point 30 which is on the common radius passing through both the arc center 26 and the tube center 21.

In' order that the sides of the projection may merge smoothly with the walls of the tube, these sides have been defined by straight portions 28 which are tangent both to the surface of tube I0 and to circular are 24. These lines 28 thus engage the tube ill at flanges 23 previously described. Lines 28 similarly merge with curved portion 24'at the points of tangency 25. By thiSl arrangement a construction has been provided which has a cross section with no reentrant curves, 1. 6., one which will be inserted within the bag to be filled and will position said bag with a. substantially uniform narrow air space 29 (Fig.

1) between the inner surface of the bag and the outer periphery of the combined cross section.

As one illustration of the dimensions of a suitable projection for use with a filling tube of 6 radius, I have found that a radius of 4 may be used for the circular arc 24 and that center 26 of this arc may be located approximately 2" inside the outer surface of tube I0. Thus, in this case, the radius of the outer curved portion is substantially two-thirds of the radius of the tube and the center of the curved portion is positioned at a distance inside tube l0 substantially equal to one-half the radius of the curved portion. The size of the bag used with this cross section was such that the width of air space 29 was sub stantially one-fourth to one-half of an inch all around the tube and blister.

With reference to Fig. 1 again it will be noted that a vertical or axial cross section of the pro jection l 1 taken in the plane of the paper (which is the same as a plane defined by the axis of tube I ii and the center 26 of curved portion 24) will be bounded by lines 31 and 32 which intersect each other at the maximum cross section, i. e., at point 30 on circular arc portion 24. These lines 3| and 32 slope symmetrically from this point of common intersection toward the upper and lower portions of tube II respectively and merge with said tube at a relatively gentle angle. In one practical embodiment of the invention an angle of 35 between these lines and the vertical wall of the tube It] has been found satisfactory.

From the foregoing details of construction it will be apparent that a projection has been provided which effectively enlarges thecross section of tube Iii in an unsymmetrical fashion at one side only of said tube and which merges with the tube smoothly in all directions, i. e'., verti cally and horizontally. I

It is my theory that such a projection prevents boiling of the flour or powdered material as a result of the combination of several factors;

first, because the bag is positioned with its axis laterally ofiset from the axis of the tube; and further because a combined cross section of the projection I1 and tube In (as shown in Fig. 3) substantially extends the walls of the bag while at the same time leaving a uniform narrow air space all around said cross section between the tube and projection on the one hand and the inner surface of the bag on the other. Finally, it is possible that the symmetrical upper and lower tapering portions of the axial cross section of the projection likewise assist to prevent the boiling action.

In other words, the auger l2 tends to swirl the powdered material circularly and symmetrically with reference to the axis of the tube [0 and auger 12. By positioning the bag slightly off center, the space into which the flour is forced is not symmetrical with respect to the auger and therefore the tendency of the material to swirl due to the action of the auger and to climb spirally upward along the outside of the tube I0 is dedecreased. Furthermore, the tapered portions of projection H offer gradually increasing resistance to those portions of the material which might tend to climb the outside of the tube on the side where there is more space between the tube and ba due to the off-center position of the bag.

Whatever the true reason for the effect, it is none the less clear that a construction of the general type described herein does accomplish the purpose of preventing boiling of the powdered material during filling. Minor variatins in the structural details used to accomplish the present purpose will be readily apparent to workers in this field, and it is intended that this invention shall include all such variations and modifications as may fall within the spirit and scope of the attached claims.

Now, therefore, I claim:

1. A packing machine for powdered material comprising a substantially vertical filling tube having an open lower end for insertion into a bag to be filled, the circumference of the tube being substantially smaller than the circumference of the bag, and a bag-positioning projection on one side only of said tube also for insertion in said bag, said projection merging smoothly with the surface of the tube both longitudinally and circumferentially, the maximum circumferential cross section of the projection and tube being characterized by the absence of reentrant curves.

2. A packing machine for powdered materials comprising a substantially vertical filling tube of circular cross section having an open lower end for insertion into a bag to be filled, and a projection on one side only of said tube also for insertion in said bag, said projection having a maximum cross section in a plane perpendicular to the axis of said tube characterized by the absence of reentrant curves and defined by: a circular arc of shorter radius than that of said tube and having its center located within said tube, and two lines tangent to both said are and the circumference of said tube, one at each side of said are andtube, the radius of said circular arc being substantially two-thirds the radius of said tube, and the center of said arc being located on a radius of the tube substantially onethird of the way from the circumference to the center of said tube.

' 3. A packing machine for powdered materials comprising a filling tube of circular cross section having an open lower end for insertion into'a bag to be filled, and a projection on one side only of said tube also for insertion in said bag, said projection having a maximum cross section in a plane perpendicular to the axis of said tube defined by: a circular arc of shorter radius than that of said tube and having its center located within said tube, and lines tangent to both said are and the circumference of said tube at each side of said tube; and said projection also having an axial cross section in the plane of said tube axis and said are center which is defined by upper and lower lines intersecting at said are and sloping gently toward said tube above and below said arc.

4. A packing machine for powdered materials comprising a filling tube of circular cross section having an open lower end for insertion into a bag to be filled, and a projection on one side only of said tube also for insertion in said bag, said projection having a maximum cross section in a plane perpendicular to the axis of said tube defined by: a circular arc of shorter radius than that of said tube and having its center located Within said tube, and lines tangent 'to both said arc and the circumference of said tube at each side of said tube; and said projection also having an axial cross section in the plane of said tube axis and said are center which tapers smoothly toward the tube below said maximum cross section.

5. In a packing machine for powdered material, a substantially vertical filling tube having an open lower end for insertion into a bag to be filled, the circumference of the tube being substantially smaller than the circumference of the bag, and an imperforate projection on one side only of said tube at the inserted end there-- e of, said projection increasing the efiective radius of said side of the tube and engaging the inside of a bag placed on the tube, thereby positioning said bag with the bag axis laterally ofiset from the tube axis.

6. A packing machine as defined in claim 3, wherein the lines defining said axial cross section meet the tube at angles of substantially 35.

7. A packing machine for powdered materials comprising a substantially vertical filling tube of circular cross section having an open lower end for insertion into a bag to be filled, means for feeding powdered material through the tube and out of said lower end, and an imperiorate projection on one side only of said tube also for insertion in said bag, said projection having a maximum cross section in a plane perpendicular to the axis of said tube defined by: a curved portion at a greater distance from the center of the tube than the length of the tube radius, and lines joining said curved portion and the circumference of said tube at each side of said tube in a substantially tangential manner.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 766,046 Kreider July 26, 1904 915,847 Frye Mar. 23, 1909 1,940,826 Stetson Dec. 26, 1933 2,012,116 Andreas Aug. 20, 1935 2,251,659 Bushman Aug. 5, 1941 2,326,881 Packer Aug. 1'7, 1943 2,426,574 Andrews Aug. 26, 1947 

